Sensitive relay



July 22, 1958 F. J. BYDALEK ET AL 2,344,685

SENSITIVE RELAY led March 24, 1953 2 Sheets-Sheet l 4 '1 L2 743 1,62 32 27 25 2 3 q[' 69' i [IdaZp/z Jfi Zj t, 221155655127 I 7261125,

lbw. 141121 1 United States Patent SENSITIVE RELAY Floyd J. Bytlalek, Gerald E. Dietz, and Adolph J. Hilgert, Milwaukee, and Russell B. Matthews, Wauwatosa, Wis., assignors to B380 lino, Milwaukee, Wis., a corporation of Wisconsin Application March 24, 1953, Serial No. 344,386

14 Claims. (Cl. 200-104) This invention relates to improvements in sensitive relay construction.

It is a principal object of the present invention to provide an improved highly efficient relay construction which is instantaneously responsive to energization by currents of predetermined relatively small magnitude and is also instantaneously responsive to deenergization.

A further object of the invention is to provide an improved sensitive relay construction of the character described the operational characteristics of which are substantially unaffected by temperature changes.

A more specific object of the invention is to provide an improved relay construction of the character described in which the range of contact movement is substantially larger than the corresponding range of armature movement, the armature being mounted for movement within the range in which the maximum force of the electromagnet is exertable thereon to thereby accomplish relatively larg'e contact movement with relatively small armature movement while at the same time maintaining relatively high contact pressures.

A further object of the invention is to provide an improved relay construction wherein thermal expansion and contraction of the magnet core and other parts cannot in any way change the positional relationship of the armature to the magnet pole faces, thus maintaining a constant range of armature movement, a constant high degree of sensitivity, and constant pull-in and drop-out values, regardless of changes in temperature to which the relay is subjected.

A further object of the invention is to provide an improved relay of the character described which is adapted to be enclosed within a hermetically sealed container, the construction of said relay being such that the build-up of temperature within the container does not impair the sensitivity or calibration of the relay and does not vary the precise adjustment of the parts of said relay.

More specifically, an object of the invention is to provide an improved relay construction of the character described utilizing a supporting frame to which the electromagnet core is fixedly connected adjacent its pole faces and on which the armature is pivotally mounted, the connections of the frame to the armature maintaining the desired positional relationships between the armature and the pole faces while at the same time permitting more remote portions of the core to move toward and away from the connections of said frame to the core during thermal expansion or contraction of the latter, for example, in response to the build-up of substantial temperatures within a sealed container in which the improved relay may be enclosed.

Another object of the invention is to provide an improved relay of the character described having biasing means normally holding the armature in a retracted position, said armature being moved against the inherent bias of said biasing means to an attracted position in flat surface contact with the pole faces of the electromagnet upon energization of the latter, there being additional energy storing means in which energy is stored by movement of the armature beyond an intermediate position in an attracting direction. The core of said electromagnet is highly permeable, so that upon deenergization of the electromagnet, the energy stored in the biasing means and in the energy storing means is sufficient to overcome the relatively small residual magnetism of the core and to instantaneously withdraw the armature from the magnet pole faces.

A further specific object of the invention is to provide an improved relay construction of the class described having means for preventing lateral movement of the electromagnet core relative to the frame during thermal expansion or contraction of the core, thereby maintaining the angularity of the pole faces substantially constant relative to said frame and insuring uniform and complete contact of the armature with said pole faces when the armature is in attracted position.

A further object of the invention is to provide an improved relay construction of the character described which is hermetically sealed, and the operation of which is substantially unaffected by the environmental conditions surrounding the enclosing container, such as the temperature, humidity, or corrosive or contaminating action of the ambient atmosphere.

A further object of the invention is to provide an improved relay construction which is well adapted for mass production manufacture, one of the features contributing thereto being novel adjustable means for readily mounting the armature on the frame in accurate positional relation to the pole faces of the magnet.

Another object of the invention is to provide an improved relay construction of the character described which is compact and is particularly well adapted for enclosure within a container of square cross-sectional shape, the structure being such as to permit maximum coil size and maximum core diameter and maximum utilization of the space within the container.

Further objects and advantages of the invention will appear from the following detailed description taken in connection with the accompanying drawings illustrating one complete embodiment of the invention mounted within an enclosing container and wherein:

Figure 1 is a side elevational view of the improved relay construction taken in the general direction indicated by the line 11 of Figure 2, parts of the container being broken away and shown in section;

Figure 2 is a plan view of the improved relay construction taken approximately along the line 2-2 of Figure 1, parts of the container being broken away;

Figure 3 is a fragmentary sectional plan view of the invention taken approximately along the lines 33 of Figures 1 and 4;

Figure 4 is a vertical sectional view taken along the lines 44 of Figures 1 and 2; and

Figure 5 is a vertical sectional view taken along the line 5-5 of Figure 4.

Referring more particularly to Figure 1 of the drawings,

the numeral 10 indicates a relay frame comprising an elongated base plate 11, and an elongated upper or clamping plate 12 spaced from and parallel to the plate 11, said plates being connected by an integral stem or coil separator 13. The frame 10 may take the form of a die casting. The plates 11 and 12 may be similar in 3 outline in plan view and preferably of the form shown in Figure 2, permitting said frame to fit diagonally within a container 75 having a substantially square cross-sectional shape.

Referring to Figure 5, the base plate 11 is formed with an elongated aperture 14 extending lengthwise thereof, the upper surface of said plate being formed at each end with a longitudinal groove 15 to accommodate the heads of anchoring rivets 16. As shown most clearly in Fig. 4, the stem 13 has an enlarged lower end portion which connects with the base plate 11 on transversely opposite sides of the aperture 14, thus leaving a lower end surface 17 of the stem exposed within said aperture. As shown most clearly in Figure 3, the stem 13 is formed with a pair of opposite concave side walls 18 and 19.

The upper plate 12 has a pair of spaced circular apertures 20 and 21, there being slots 22 and 23 communicating respectively with said apertures and extending longitudinally outwardly to the edges of said plate. The margins of the slots 22 and 23 are normally spaced apart slightly prior to the assembly of other parts of the relay thereon during manufacture. On each side of the slot 22 the plate 12 is provided with an integral upstanding lug 24, and at each side of the slot 23 there is an integral upstanding lug 25. The lugs 24 and 25 are transversely apertured to receive rivets 26 and 27 for a purpose to be hereinafter described.

An elongated U-shaped magnet frame or core 28 is clampingly engaged by and hung from the frame plate 12 in a novel manner. The core 28 has a pair of legs 29 and 30 which are preferably round in cross-section, said legs being connected at one end by an integral transverse connecting portion 33 which may take the form of a bar. The legs 29 and 30 are positioned on opposite sides of the stem 13 and extend through the apertures 20 and 21 of the clamping plate 12, terminating in pole faces 31 and 32, respectively, which are preferably coplanar and positioned close to the plate 12. In assembling the magnet core 28 to the frame 10, the opposing surfaces of the slots 22 and 23 are drawn into abutment by the installation of the rivets 26 and 27, the relationship of the diameter of the core legs to that of the apertures 20 and 21 being such that the portions of the plate 12 surrounding the legs fixedly clamp said legs adjacent their pole faces so that the core 28 hangs from the plate 12 in the manner shown.

The transverse portion 33 of the core 28 is positioned within the elongated aperture 14 of the plate 11 and is below the lower end surface 17 of the stem 13, as shown in Figures 4 and 5. Referring to Figure 4, a pin 34 is pressed fitted into a suitable longitudinal bore 35 in the stem end face 17, and the bar 33 of the core is bored, as at 36, to receive the pin 34 in slip-fit relationship. Thus, the closed end 33 of said core is free to move toward and away from the clamping plate 12 in the event of thermal expansion or contraction of said core. The pin 34 and bore 36 prevent any lateral movement of the core during such thermal expansion and contraction.

The magnet core 28 is preferably made of a solid piece of metal having high permeability, and hence, low residual magnetism. One type of metal which has Worked satisfactorily in the core 28 is a well known and commercially available steel known in the trade by the name 4750 steel. The unitary construction of the core 28 prevents losses occurring in secondary air gaps frequently found in non-unitary cores.

A pair of induction coils 37 and 38 surround the core legs 29 and 36 in insulated relationship, said coils extending between and being insulated from the plates 11 and 12 as shown in Figure 5. As shown most clearly in Figure 3, the concave surfaces 18 and 19 conform to the contours of the coils 37 and 38. The stem 13 is provided with a pair of paralled transverse bores 40 and 41 (Figures 4 and 5) to receive a pair of bolts 42 and 43, respectively, and an insulating wrapping 39 surrounds an end portion of each of the coils 37 and 38 adjacent said bolts.

A mounting bracket or plate 44 is provided with a pair of spaced slots 45 and 46 for receiving the bolts 42 and 43, said plate being positioned on a fiat side wall portion of the stem 13 as shown. The slots 45 and 46 permit longitudinal adjustment of the bracket 44 relative to the stem 13. The bolts 42 and 43 also provide a means for mounting a pair of electrical contact stacks 47 and 48 on opposite sides of the stem, the stack 47 being outwardly juxtaposed to the bracket 44. Nuts 42' and 43 may be used to secure the bracket 44 and stacks 47 and 48 in position on the bolts 42 and 43.

The contact stack 47 comprises a pair of insulatably mounted spaced depending resilient contact arms or leaf springs 49 and 58 having a resilient biasing contact arm or leaf spring 51 of greater length positioned therebetween. The arms 49 and 58 have integral contact but tons 49' and 54 at their lower ends, and the arm 51 has an integral contact button 52 engageable with the button 49. As shown, the arm 51 projects beyond the ends of the arms 49 and 5t), and said arm is provided with a non-resilient metallic reinforcement 53 which may be integral therewith. The reinforcement 53 may take the form of a metal bar which also serves as a contact member normally in electrical contact with the contact 50 due to the inherent bias of the arm 51. Contact arms 49, 511, and 51 thus form a single pole doublethrow switch wherein the arm 51 is normally in electrical contact with the arm 50. The reinforcement 53 prevents deformation of the end portion of the arm 51 outwardly of the contacts 49', 5t) and 52.

The contact stack 48 may be similar to the stack 47, having insulatably mounted resilient depending contact arms 54 and 55, and a resilient biasing contact arm or leaf spring 56 provided respectively with integral contact buttons 54, 55 and 57. The arm 56 has an integral non-resilient metallic reinforcement 58 which also serves as a contact normally engaging the contact 54' due to the inherent bias of the contact arm 56. The reinforcement 58 prevents deformation of the end portion of the arm 56 outwardly of the contacts 54, 55' and 57.

Referring to Figures 3 and 4, the mounting bracket 44 is provided with a pair of spaced parallel outwardly and upwardly projecting apertured ears 59 and 61 which provide bearings for a transverse pivot pin 61. A pivot plate 62, which may be generally rectangular in plan view as shown in Figure 2, is spaced above and extends transversely over the plate 12 of the frame 11 For the purpose of rigidity, the plate 62 may have a depressed central area as shown in Figures 4 and 5.

A pair of elongated rigid contact actuating arms 63 and 64 depend from one side of the plate 62 at opposite ends thereof, said arms extending alongside the contact stacks 47 and 48 respectively as shown in Figures 1 to 3. In Figure 4 the position of the arms 63 and 64 is shown by dot-and-dash lines for clarity. The lower ends of the arms 63 and 64 carry transverse pins 65 on which insulating contact rollers 66 and 67 are mounted. The roller 66 engages the reinforcement 53 on contact arm 51, and the roller 67 engages the reinforcement 58 on contact arm 56. The upper end of the contact actuating arm 63 is provided with a transverse bore 63' to receive the pivot pin 61. Transversely opposite the arm 63 the pivot plate 62 is provided with a depending car 68 having a transverse bore through which the pin 61 also projects. The car 68, arm 63, pin 61, and bracket 44 provide a pivotal mounting for the pivot plate 62.

An armature 69 of highly permeable metal such as S. A. E. 4750 steel, is fixed to the underside of the pivot plate 62, as by rivets 70. The armature preferably takes the form of an elongated fiat plate which may be shaped as shown in Figure 2, said armature being disposed above the pole faces 31 and 32 of the magnet core legs 29 and 30 and beingmo'vable with the plate toward and'a'way from said pole faces upon pivotal movement of the plate 62. The vertical adjustability of the mounting bracket 44 provides for the securement of said bracket to the stem 13, in the precise position permitting fiat surface contact of the armature with the pole faces 31 and 32.

Means are preferably provided for maintaining a minimal effective gap between the armature and the pole faces when the armature is in attracted position relative to said pole faces. This means may take the form of a thin layer of non-magnetic plating metal on the armature, for example a layer of copper, tin or chromium having a thickness on the order of .0003 inch. Thus, while the plated armature can move into flat surface contact with the magnet pole faces, the permeable portion of the armature is spaced from the pole faces a distance equal to the plating thickness. This effective air-gap, while permitting operation of the armature close to the pole faces where maximum attractive forces can be exerted thereon by the magnet, minimizes the effect of variables, such as slight variations in core permeability, out of fiatness of related parts, or variation in spring force of the normally open contacts, to the point where said variables do not impair the sensitivity of the relay.

The resilient biasing contact arms 51 and 56 bear against the contact rollers 66 and 67 in a manner to urge the latter to the right (as viewed in Figure 4), to thereby normally bias the armature 69 to retracted position with respect to the pole faces 31 and 32. An adjustable stop screw 71 may be threaded into the upper frame plate 12 adjacent the edge of the armature, the head of said screw overlapping the armature and being engageable thereby. The stop screw 71 defines the limit of the armature travel away f-rom the pole faces 31 and 32. In the illustrated embodiment of the invention, the armature is spaced from the pole faces approximately .003 inch when in contact with the screw 71. e The biasing contact arms 51 and 56 are of such a character that their biasing force is the maximum possible consistent with the attractive force of the electromagnet and hence with the sensitivity of the relay. Thus, maximum possible contact pressures between the metallic reinforcement 53 and the button 50' and between the reinforcement 58 and the button 54 are attained when the elec tromagnet is deenergized, while at the same time sensitivity is also attained. The highest possible normally closed contact pressures are desirable to prevent chattering from vibration or the like. The character of the contact arms 50 and 54 is such that they are not substantially deformed by the biasing force of the contact arms 51 and 56 thereagainst.

Upon energization of the magnet coils 37 and 38 the armature 69 is attracted to the pole faces 31 and 32, and it immediately moves into flat contacting engagement with said pole faces. As the armature so moves, it pivots the plate 62 therewith, and swings the contact actuating arms 63 and 64 and rollers 66 and 67 to the left (as viewed in Figure 4) against the inherent bias of the contact leaves 51 and 56. Contact leaves 51 and 56 are thereby moved out of electrical contact with leaves 50 and 54 and into electrical contact with the leaves 49 and 55, respectively, deforming the latter slightly after making contact therewith. The deformation of the leaves 49 and 55 stores energy in said leaves for a purpose to be hereinafter described, and it also provides relatively high contact pressures at the newly made contacts.

The effective lever arms provided by the pivot plate 62 and contact actuating arms 63 and 64 cause movement of the rollers 66 and 67 through a range which is substantially greater than the range of movement of the armature 69. The contacts 52 and 57, therefore, also have a correspondingly greater range of movement than does the armature. In the illustrated embodiment of the invention, the range of contact movement is on the order-- of .012 inch as compared with .003 inch of corresponding armature movement. For any armature movement there is a direct and corresponding movement ofthe contacts 52 and 57, since the reinforcements 53 and 58 prevent deformation of the portions of leaves 51 and 56 outwardly of said contacts. Lost motion is thus avoided, and direct action is insured.

Upon deenergization of the magnet coils 37 and 38, either completely or to a predetermined lower drop-out value, the core 28 quickly loses magnetism due to its high permeability. The energy stored up in the deformed leaves 49, 51, 55, and 56 quickly overcomes the relatively small residual magnetism left in the core and pulls or kicks off the armature from the pole faces 31 and 32. The leaves 49 and 55 return to their undeformed state as the armature leaves the pole faces, and the in herent bias of the leaves 51 and 56 returns the armature and contact assembly to the normal position shown in Figure 4.

As is well known, the attractive force exerted by an electromagnet on an armature increases rapidly as the armature approaches the magnet pole faces. To put it another way, the attractive force varies inversely with the air gap. stored in the contact leaves 49 and 55 during that portion of the armature travel during which maximum attractive force is exerted on the armature by the energized electromagnet, at which time said force substantially exceeds the bias of the leaves 51 and 56. This occurs just prior to and during engagement of the armature with the pole faces. Similarly, the attractive force of the residual magnetism of the core 28 is at its maximum when the armature is in contact with the pole faces, said force decreasing rapidly as the armature moves away from said pole faces. In the improved relay construction, the energy stored in the leaves 49 and 55 plus that stored in the leaves 51 and 56' is sufficient to instantaneously pull the armature free of the pole faces whenever the coils 37 and 38 are deenergized to below a predetermined drop-out value. As the armature 69 moves out of contact with the pole faces, leaves 49 and 55 return to their normal undeformed state, and, since the attractive force of the cores residual magnetism by this time has substantially decreased, the inherent bias of the leaves 51 and 56 is suflicient to return the armature to its normal retracted position.

The storing of energy during attracting movement of the armature permits the utilization of maximum power available from the electromagnet. Since the armature movement is levered up by the contact actuating arms 63 and-'64, only a relatively small range of armature movement is necessary to provide the desired range of contact movement. This feature, coupled with the fact that the armature is operated within the range in which the maximum force of the electromagnet is exerted thereon, provides relatively large contact movement and relatively high contact pressures with relatively small armature movement.

The range of armature movement, and the normal spacing of the retracted armature from the pole faces remains constant regardless of thermal expansion and contraction of the core 26, due to the fact that the core is clamped by the plate 12 adjacent the pole faces. The angular relationship of the pole faces to the plate 12 is maintained by the pin 34 which prevents any substantial lateral movement of the core relative to the frame 10 during thermal expansion and contraction of the core. The maintenance of constant armature to pole face relationship regardless of temperature variations insures that the improved relay under all conditions will retain a uniformly high degree of sensitivity. The improved structure also insures that pull-in and drop-out values of the relay remain constant, with the differential between said pull-in and drop-out values therefore also remaining constant.

It is apparent, therefore, that energy is As shown in the illustrated embodiment, the relay mechanism so far described may be mounted within a plug-in type enclosure 75 having a square cover 72 with a peripheral upturned lip 73. A pair of bushings 74 surround the rivets 16 and hold the frame base plate 11 spaced from and parallel with the cover 72. The rivets 16 fixedly connect the plate 11 to the cover 72, as shown most clearly in Figure 5. A rectangular cup-shaped container 75' having a square transverse cross-sectional shape fits telescopically over the cover 72 and may have a snug fit with the frame 10, as shown in Figures 2 and 3. The container 75' is sealingly connected to the cover 72, as by soldering, and is preferably provided with an evacuating tube 76.

While two single-pole-double-throw switches are shown in the illustrated embodiment, any desired and suitable combination or types of switches may be provided, as by simply subtraetingcontact leaves from the stacks 47 and 48. The leads from the coils 37 and 38 and from all of the switch contacts are suitably connected to separate prongs 77 which may sealingly project through a suitable glass seal in the cover 72. The cover 72 may also be provided with externally projecting studs 78 for securement purposes.

In assembling the improved relay, the pin 34 is press fitted into the bore 35 in the stem 13 of the frame 10, and the coils 37 and 38 are positioned on opposite sides of said stem between the plates 11 and 12. The magnet core 28 is then inserted through the slot 14 in the plate 11, the legs of said core being inserted coaxially through said coils and through the apertures and 21 in the clamping plate 12. As the core is thus inserted, the pin 34 enters the bore 36 in the transverse core portion 33 with a slip fit. With the pole faces of the core spaced a predetermined short distance from and parallel with the upper surface of the plate 12, the rivets 26 and 27 are installed in the lugs 24 and to draw the latter together and thereby fixedly clamp the core 28 in the apertures 20 and 21 of the plate 12. Thus the core 28 is hung from the plate 12 and is directly fixed to said plate only.

The mounting bracket 44 and the contact stacks 47 and 48 are then assembled on the stem 13 by means of the bolts 42 and 43 and nuts 42' and 43', the latter being left loose to permit subsequent adjustment of the bracket 44. The armature and arm assembly are then pivotally connected to the mounting bracket 44 by means of the pivot pin 61. The armature is then pressed flat against both pole faces of the core 28, thereby causing the bracket 44' to automatically assume its proper operating position. While the armature is thus held, the nuts 42 and 43 are tightened to secure the bracket 44 and stacks 47 and 48 in operative position on the stem 13.

The frame 10 is then secured to the cover 72 by means of the rivets 16' and the bushings 74, and the lead wires from the contacts and the coils are soldered or otherwise connected to the prongs 77. The relay is then tested for pull-in and drop-out values and is adjusted, if necessary, by bending the contact leaves or the contact actuating arms as necessary. After testing, the relay is then placed in the container 75 and the cover 72 soldered to said container.

In the preferred form of the invention, the sealed container 75 is evacuated through the tube 76, after which the container is filled with an inert gas, such as dry nitrogen. The container is thereafter again evacuated and filled with dry nitrogen preferably mixed with a small quantity of helium. The container is then tested for leaks, preferably by means of a spectrometer which is capable of readily detecting any traces of the helium which might leak from the container. If no leaks are detected, the tube 76 is pinched off and sealed.

All of the materials used in the improved relay are of a stable character which can successfully withstand the evacuation operation. It will be noted that the insulating wrapping 39 does not completely cover the coils 37 and 38. By leaving the coils partially unwrapped, rapid and complete evacuation of the container can be attained with no adverse effect on the coils.

The diagonal disposition ofthe frame 10 within the container permits the utilization of the maximum amount of space within said container. Larger diameter coils 37 and 38 having a greater number of ampere-turns are permitted by this disposition, so that the strongest possible magnet is provided within the spacial limits of the container 75. It will also be noted that the diagonal disposition of the frame 10 provides ample space for the accommodation of the contact stacks 47 and 48, as well as of the contact actuating arms 63 and 64.

The improved relay construction is well adapted for mass production, since operation of the armature within the maximum power range of the electromagnet (into actual contact with the pole faces) permits relatively wide tolerances in contact spacing as well as maintenance of maximum contact pressures. On the other hand, the armature-to-pole-face air gap and the position of the armature mounting relative to the pole faces can be precise-1y and quickly adjusted. These features, combined with the fact that the armature-to-poie-face relationship is maintained constant regardless of thermal expansion or contraction of the magnet core, provide a particularly sensitive and eflicient device.

The uniformity and sensitivity of operation which is maintained by the improved relay regardless of temperature changes make it particularly suited for operation in a sealed container wherein all adjustments must be made once and for all before the container is sealed. The adjustments must thereafter remain constant to provide uniform operational characteristics despite varying conditions of temperature, humidity, and other environmental conditions. The hermetically sealed container tends to insure constant environmental conditions within the cont ainer except for temperature.

To illustrate the sensitivity of which the improved relay construction is capable, one form of the invention can be actuated or pulled in by six milliwatts ofelectric power and will drop out by deenergization to two milliwatts of power. The release time of the improved relay (the time necessary for the armature to drop out and return to retracted position after cut-off of the energizing current) is on the order of seven milliseconds. This high degree of sensitivity and other operational characteristics are maintained substantially constant throughout the entire temperature range to which the relay might be subjected. Tests have shown that the desired sensitivity and uniformity of operation are maintained by the improved relay throughout a temperature range of from 65 centigrade to centigrade.

The illustrated embodiment of the invention is for the purpose of disclosure only, and is not to be construed as in any way defining the limits or scope of the invention. Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the appended claims.

What we claim as the invention is:

1. In a compact highly sensitive relay or the like adapted for uniform operation at widely variant temperatures, the combination of: a frame having a transverse extent and having an elongated stern portion projecting normal to said transverse extent; a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, said legs terminating in pole faces and being fixedly connected to said transverse frame extent adjacent said pole faces, said core also having a closed end portion extending around the end of said stem opposite said transverse extent and free to move relative to said extent and stem, said stem being provided with a longitudinal bore; and a longitudinal pin. having a portion positioned in said stem bore, the closed end portion of said core being provided with a longitudinal bore in which a portion of said pin is positionedto provide a longitudinally slidable connection between said stem and the closed end portion of the core, said connection preventing relative transverse movement therebetween While permitting longitudinal movement therebetween.

2. In a compact highly sensitive relay or the like adapted for uniform operation at widely variant temperatures, the combination of: a frame having a transverse extent and having an elongated stem portion projecting normal to said transverse extent; a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, said legs terminating in pole faces and being fixedly connected to said transverse frame extent adjacent said pole faces, said core also having a closed end portion extending around the end of said stem opposite s-aid transverse extent and free to move relative to said extent and stem; and a longitudinal pin carried by said stem, the closed end portion of said core being provided with a longitudinal bore in which said pin is slidably received to provide a longitudinally slid'able connection between said stem and the closed end portion of the core, said connection preventing relative transverse movement therebetween while permitting longitudinal movement therebetween.

3. In a compact highly, sensitive relay or the like adapted for uniform operation at widely variant temperatures, the combination of: a frame having a transverse plate portion and having an elongated stem portion projecting normal to said transverse plate, said plate having a pair of spaced apertures therethrough positioned on opposite sides of said stem and having a slot therethrough communicating with each of said apertures; a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, said legs projecting through said plate apertures and terminating in pole faces adjacent said plate, said core also having a closed end portion extending around the end of said stem opposite said piate; connecting members drawing the margins of said plate slots together adjacent said apertures to cause said plate to fixedly clamp said core legs, the closed end portion of said core being free to move relative to said plate and stem; and a longitudinal pin carried by said stem, the closed end portion of said cor-e being provided with a longitudinal bore in which said pin is slidably received to provide a longitudinally slidable connection between said stem and the closed end portion of the core, said connection preventing relative transverse movement therebetween while permitting longitudinal movement therebetween.

4. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame, a magnet core having a pole face at one end and formed with an opening at its opposite end substantially at right angles to said pole face, said core being fixedly connected to said frame adjacent said pole face, means on said frame slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longtiudinal movement therebetween, and an armature also connected to said frame and coacting with said pole face for movement between an attracted position and a retracted position relative to said pole face, the adjacency to said pole face of said fixed core-to-frame connection and the prevention of relative transverse movement between the ends of said core maintaining the relationship of said armature positions to said pole face constant despite temperature variations.

5. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame, a magnet core having a pole face at one end and formed with an opening at its opposite end, said hole having an axis substantially at right angles to said pole face, said core being fixedly connected to said frame 10 adjacent said pole face, an extension fixed to said frame and having an axis substantially at right angles with respect thereto and slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longtiudinal movement therebetween, and an armature also connected to said frame and coacting with said pole face for movement between an attracted and a retracted position relative to said pole face, the adjacency to said pole face of said fixed core-to-frame connection and the prevention of relative transverse movement between the ends of said core maintaining the relationship of said armature positions to said pole face constant despite temperature variations.

6. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame, a magnet core having a pole face at one end and formed with an opening at its opposite end substantially at right angles to said pole face, said core being fixedly connected to said frame adjacent said pole face, a pin fixedly positioned in said frame substantially at right angles with respect to said pole face when said frame and core are connected, said pin slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longitudinal movement therebetween, and an armature also connected to said frame and coacting with said pole face for movement between an attracted position and a retracted position relative to said pole face, the adjacency to said pole face of said fixed coreto-frame connection and the prevention of relative transverse movement between the ends of said core maintaining the relationship of said armature positions to said pole face constant despite temperature variations.

7. In a relay or the like adapted for uniform opera tion at widely variant temperatures, the combination of, a frame, a U-shaped magnet core having a pair of pole faces at one end and being formed with an opening at its opposite end substantially at right angles to said pole faces, said core being fixedly connected to said frame adjacent said pole faces, means on said frame slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longitudinal movement therebetween, and an armature also connected to said frame and coacting with said pole faces for movement between an attracted position and a retracted position relative to said pole faces, the adjacency to said pole faces of said fixed core-to-frame connection and the prevention of relative transverse movement between said ends of said core maintaining the relationship of said armature positions to said pole faces constant despite temperature variations.

8. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame having a clamping plate portion provided with a pair of spaced apertures and with a slot therethrough communicating with each of said apertures, a U-shaped magnet core having a pair of legs projecting through the apertures in said plate and terminating in pole faces adjacent said plate, said magnet having a closed end portion opposite said pole faces formed with an opening substantially at right angles to said pole faces, means drawing the margins of said plate slots together adjacent said apertures to cause said plate to fixedly clamp said core legs, means on said frame slidably engaging the opening in said core to prevent transverse movement of said closed end portion with respect to said pole faces while permitting relative longitudinal movement therebetween, and an armature also connected to said frame and coacting with said pole faces for movement between an attracted position and a retracted position relative to said pole faces, the adjacency to said pole faces of said fixed core-to-frame connection and prevention of relative transverse movement between the closed end portion of said core and said pole faces maintaining the relationship of said armature positions to said pole faces constant despite temperature variations.

9. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, aframe having a transverse extent and having an elongated stem portion projecting normal to said transverse extent, a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, said legs terminating in pole faces and being fixedly connected to said transverse frame extent adjacent said pole faces, said core also having a closed end portion extending around the end of said stem opposite said transverse frame extent and being formed with an opening substantially at right angles to said pole faces, means on the end of said stem opposite said transverse frame extent slidably engaging the opening in said core closed end portion to prevent transverse movement of said core closed end portion with respect to said pole faces while permitting relative longitudinal movement therebetween.

10. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame, a magnet core having a pole face at one end and formed with an opening at its opposite end substantially at right angles to said pole face, said core being fixedly connected to said frame adjacent said pole face, and means on said frame slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longitudinal movement therebetween.

11. In a relay or the like adapted for uniform operation at widely variant temperatures, the combination of, a frame, a U-shaped magnet core having a pair of pole faces at one end and being formed With an opening at its opposite end substantially at right angles to said pole faces, said core being fixedly connected to said frame adjacent said pole faces, and means on said frame slidably engaging the opening in said core to prevent transverse movement of said opposite end with respect to said one end while permitting relative longitudinal movement therebetween.

'12. In a compact highly sensitive relay or the like adapted for uniform operation at widely variant temperatures in a relatively small volumetric space, the combination of, a container of least possible volumetric dimension for the relay having a substantially square cross section, said relay having volumetric shape and size substantially equal to the internal volumetric dimension of said container characterized by having a frame including a transverse plate portion disposed within said container along a first diagonal of said cross section and an elongated stem portion projecting normal to said transverse plate, a magnet core extending in the same general direction as said stem, means fixedly clamping said magnet core to said transverse plate, said core also having an end portion free to move relative to said plate and stem, means providing a connection between said stern and said end portion to prevent relative transverse movement therebetween while permitting longitudinal movement therebetween, at least one contact stack positioned adjacent said stem in alignment With the other diagonal of said cross section, and an armature pivotally mounted on an axis substantially parallel to said first diagonal but positioned to one side thereof along said other diagonal, said armature having a contact actuator movable in a plane substantially coincidental with said other diagonal, the length of frame being substantially equal to the length of said first diagonal and the length of said contact stack, armature and actuator being substantially equal to the length of said other diagonal to thereby afford a highly compact relay.

13. In a compact highly sensitive relay or the like adapted for uniform operation at widely variant temperatures in a relatively small volumetricspace, the combination of: a container of least possible volumetric dimension for the relay having a substantially square cross section, said relay having volumetric shape and size substantially equal to the internal volumetric dimension of said container characterized by having a frame including a transverse plate portion disposed within said container along a first diagonal of said cross section and an elongated stem portion projecting normal to said transverse plate, a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, means fixedly clamping said magnet core to said transverse plate to provide a pair of pole faces adjacent said plate, said core also having a closed end portion extending around the end of said stem opposite said plate and being free to move relative to said plate and stem, means providing a connection between said stem and the closed end portion of the core to prevent relative transverse movement therebetween while permitting longitudinal movement therebetween, at least one contact stack positioned adjacent said stem in alignment with the other diagonal of said cross section, and an armature pivotally mounted on an axis substantially parallel to said first diagonal but positioned to one side thereof along said other diagonal, said armature having a contact actuator movable in a plane substantially coincidental with said other diagonal, the length of frame being substantially equal to the length of said first diagonal and the length of said contact stack, armature and actuator being substantially equal to the length of said other diagonal to thereby afford a highly compact relay.

14. In a compact highly sensitive relay or the like adapted for uniform operation at Widely variant temperatures in a relatively small volumetric space, the combination of: a container of least possible Volumetric dimension for the relay having a substantially square cross section, said relay having volumetric shape and size substantially equal to the internal and volumetric dimension of said container characterized by having a frame including a transverse plate portion disposed Within said container along a'first diagonal of said cross section and an elongated stem portion projecting normal to said transverse plate, a U-shaped magnet core having a pair of legs positioned on opposite sides of and extending in the same general direction as said stem, means fixedly clamping said magnet core to said transverse plate, said core also having a closed end portion extending around the end of said 'stem opposite said plate and being free to move relative to said plate and stem, a longitudinal pin carried by saidstem, the closed end portion of said core being provided with a longitudinal bore in which said pin is slidably received to provide a longitudinally slidable connection between said stern and the closed end portion of the core'to prevent relative transverse movement therebetween while permitting longitudinal movement therebet een, at least one contact stack positioned adjacent said stem in alignment with the other diagonal of said crosssection, and an armature pivotally mounted on an axis'substantially parallel to said first diagonal but positioned to one side thereof along said other diagonal, said armature having a contact actuator movable in a plane substantially concidental With said other diagonal, the length of frame being substantially equal to the length of said first diagonal and the length of said contact stack, armature and actuator being substantially equal to the length of said other diagonal to thereby afford a highly compact relay.

.References'Cited in the file of this patent UNITED STATES PATENTS 797,628. Stowe Aug.22, 1905 1,022,065 Dean Apr. 2, 1912 1,207,736 'Forsberg Dec. 12, 1916 1,636,609 Klann July 19, 1927 (,0ther referencespu following page) '13 UNITEQ STATES PATENTS Mead June 10, 1930 Allen Dec. 20, 1932 Bogle Aug. 14, 1934 Richmond Sept. 24, 1935 Baum Jan. 7, 1941 Ray Aug. 7, 1945 14 Wood Apr. 2, 1946 King et a1. Dec. 10, 1946 Fisher Aug. 5, 1947 Deakin Feb. 27, 1951 Hall et a1 Oct. 16, 1956 FOREIGN PATENTS France May 26, 1947 

